“Cell division is part of the cell

cycle”Section 3.2 & 3.3

Smart Notebook

Do Now

• Label the following diagram

• 1- chromosome

• 2- chromatid

• 3- centromere

Do Now

• Through a light microscope, what parts of the cell would you look at to determine what stage of mitosis the cell is in?

Objectives

• Describe the main events of the cell cycle

• Differentiate interphase from mitosis

• Construct a cell cycle model from paper plates.

Cell Cycle• “normal sequence of development and division of a cell”

• Two main phases: Interphase & M-phase (Mitosis)

Interphase• There is no division in interphase, just growth.

G1: organelles duplicate, cell grows

S: DNA replicates (is copied)

G2: cell grows, prepares to divide

M-phase (Mitosis)• Mitosis= “nuclear division”

• PMAT+ C

• Prophase

• Metaphase

• Anaphase

• Telophase

• Cyokinesis

Mitosis• Creates 2 genetically IDENTICAL daughter cells.

Prophase• DNA condenses to form chromosomes.

• Each chromosome has 2 chromatids and a centromere

• The nuclear membrane disappears

Metaphase – “Middle”

• Chromosomes line up in the middle of the cell at the “equator”

Anaphase – “away”• Chromatids split

• Spindles pull to opposite sides of the cell AWAY from each other

Telophase• 2 nuclei form

• Nuclear membrane forms around each group of chromosomes.

• The chromosomes become chromatin again.

Cytokinesis

• Division of the cytoplasm.

• Occurs differently in plant and animal cells.

• 2 new daughter cells!

Cytokinesis

• Animal Cells:

• Membrane pinches together and forms a cleavage furrow until the cells separate.

Cytokinesis

• Plant Cells:

• Cell plate forms which becomes the cell wall and divides the two cells.

Section 3.3

• Eukaryotic cells divide by mitosis and cytokinesis.

• Ex: skin cells apart of skin tissue (aren’t independent)

• Most unicellular organisms use cell division to reproduce through asexual reproduction.

• Asexual Reproduction: one organisms produces one or more new organisms that are identical to itself and that live independently of it

“Both sexual and asexual reproduction involve cell division”

Binary Fission

• A form of asexual reproduction occurring in prokaryotes.

• The parent organism splits in two, creating two independent daughter cells.

• Genetically all the same!

Budding - Organism develops tiny buds on its body.

• Genetic material the same!

• Can bud anywhere OR specialized cells in certain parts of the body.

• Detaches when it reaches a certain size

• Both unicellular and multicellular can reproduce by budding.

Hydra

Regeneration

The process of new tissue growth at sites with

wounds or lost limbs.

Bacteria

Many bacteria have a very short generation time.

Some can have a new generation of cells in less than 30 min.